Motor vehicle differential gear assemblies are generally known and are used to transmit torque from an input shaft to a pair of output axle shafts extending generally transverse relative to the input shaft while at the same time, allowing for differential rotation of the output shafts as necessarily occurs during turning of the vehicle. In general, the differential gear assembly includes a differential case rotatably supported within an axle housing and a ring gear coupled to rotate therewith that is driven by a pinion gear coupled to the input shaft. Therefore, the differential case rotates within the axle housing in response to rotation of the torque input shaft.
The inner ends of the output shafts extend into the differential case and include side gears splined or otherwise coupled to rotate therewith while at least one pair of pinion mates is provided between and in meshing engagement with both side gears. Each pair of pinion mates are supported for rotation on a cross-pin that is secured to the differential case such that upon rotation of the case, the pinion mates transfer torque to the side gears. While in many instances, one pair of pinion mates is adequate to transmit the torque from the differential case to the side gears, in heavy duty or high performance applications, an additional pair of pinion mates may be provided to form a four pinion mate differential having increased strength relative to the two pinion mate differential having only one pair of pinion mates.
The increased complexity associated with a four pinion mate differential increases the cost of the differential and the assembly time. Because of the increased number of interrelated components, extra care must be taken to ensure that all components are within manufacturing tolerances so that the components will fit together as required during assembly. The increased complexity associated with a four pinion mate differential typically requires the use of a two piece differential case that is generally more expensive to manufacture and assemble and not as strong as a one piece differential case.
One piece differentials having four pinion mates have been developed but have not proven satisfactorily strong nor have they allowed for the easy assembly of both the pinion mates and also the related components such as the axle shaft retainer clips that secure the axle shafts and side gears in position. For example, prior systems may add a second cross pin that is connected to only the primary cross pin. In such a system, it is likely that damage to the differential will result at the connection between the primary and secondary cross pins.